LAS VEGAS — Pete Buttigieg, the mayor of South Bend, Ind., on Saturday directly confronted one of his biggest vulnerabilities as a contender for the Democratic presidential nomination: running as a white man who has led a life of relative privilege at a time when many in his party are eager for a woman or a minority candidate to become their next leader.
Speaking at a fund-raiser for lesbian, gay, bisexual and transgender causes, Mr. Buttigieg drew on his own experiences as a gay man in a predominantly straight society. But he also rejected the idea that “there are equivalencies” in the forms of discrimination experienced by different minority groups and individuals.
“I may be part of the L.G.B.T.Q. community. But being a gay man doesn’t even tell me what it’s like to be a trans woman of color in that same community, let alone an undocumented mother of four or a disabled veteran or a displaced autoworker,” he said at the event, hosted by the Human Rights Campaign.
Mr. Buttigieg drew on the experiences of several historically oppressed groups and the political movements that brought greater social and political equality, including Latino farm laborers, black civil rights activists and the early gay rights movement that grew out of the Stonewall rebellion in Greenwich Village. He called for “the beginning of a new form of American solidarity” among people who understand that they live “in a society that sees us for what makes us all different.”
At the same time, Mr. Buttigieg warned that identity politics can be corrosive on the right and the left, and said he feared that it often drove people in his party with a common purpose bitterly apart.
“The wall I worry about most isn’t the president’s fantasy wall on the Mexican border that will never get built anyway,” he said, jabbing at President Trump, who has been lobbing insults at Mr. Buttigieg all week. “What I worry about are the very real walls being put up between us as we get divided and carved up.”
Then he made an explicit appeal to his audience. “And what every gay person has in common with every excluded person of every kind is knowing what it’s like to see a wall,” he said.
Mr. Buttigieg, 37, who graduated from Harvard and Oxford, spoke with pride and amazement about being featured on the cover of Time magazine with his husband, Chasten, under the headline, “First Family,” something he said he never could have contemplated was possible when he was a closeted teenager.
“I am ready to use my story, my energy, my alliances,” he added, “and yes, my privilege, to throw myself into tearing down those walls.”
One of the biggest challenges for Mr. Buttigieg so far has been persistent doubts about whether he could appeal to voters beyond the mostly white crowds who have been showing up at his campaign rallies in growing numbers. He has also faced questions about his record in South Bend, including the firing of the city’s first black police chief, and about the frustration among some African-Americans that they have not benefited equally from the city’s economic resurgence, which he often highlights. In recent weeks, Mr. Buttigieg has reached out to black leaders and campaigned at events held by minority groups.
Mr. Buttigieg’s appearance at the dinner on Saturday capped a West Coast swing that included sold-out fund-raisers in the Bay Area and Los Angeles, adding more money to coffers that are already larger than the vast majority of his rivals for the Democratic nomination. One fund-raiser was at the home of the actress Gwyneth Paltrow; another was at the Abbey, a popular West Hollywood gay bar.
As he and his campaign have evolved — he started out as a curiosity and in a matter of weeks became one of the top-tier candidates in a crowded Democratic field — Mr. Buttigieg has been successful in attracting the financial support of many of the wealthy and famous people in Hollywood, Silicon Valley and Wall Street who helped raise millions of dollars for Barack Obama and Hillary Clinton.
He has also attracted a new and notable foe: the president. After initially ignoring Mr. Buttigieg and reserving his ridicule for other potential Democratic challengers, Mr. Trump has commented on the mayor twice in the last few days.
“Representing us against President Xi of China,” Mr. Trump said at a rally in Florida on Wednesday night, his voice thick with sarcasm. “That’d be great.”
Then he compared Mr. Buttigieg to the adolescent, gaptoothed cartoon mascot for Mad magazine. “Alfred E. Neuman cannot become president of the United States,” the president said in an interview with Politico on Friday
Mr. Buttigieg, who has attempted to make much of his argument to voters about the need for generational change in politics, professed to be a bit puzzled by the Newman reference.
The humor magazine’s heyday was years before he was born. “I had to Google that,” he said when asked about it. “I guess it’s a generational thing.”
And asked to respond to Mr. Trump’s criticism that he could not handle negotiating with the Chinese, Mr. Buttigieg said in an interview that he would be happy to put his diplomatic skills up against the president’s.
“There’s very little evidence that this White House knows what it’s doing when it comes to China,” he said.